Method of regulating the cooling effect of a refrigerant



P. SCHLUMBOHM Jan. 117, 1933.

METHOD OF REGULATING THE COOLING EFFECT OF A REFRIGERANT Filed March16,. 1931 Patented Jan. 17, 1933 UNITED STATES PATENT; OFFICE PETERSCHLUMIBOHM, OF BERLIN, GERMANY, ASSIG-NOR TO THE AMERICAN THERMOSBOTTLE COMPANY, OF NORWICH, CONNECTICUT, A CORPORATION OF OHIO METHOD OFBEGULATING THE COOLING EFFECT OF A REFRIGEBANT Application filed March16, 1931, Serial No. 523,107, and in Germany March 18, 1930.

My invention relates to a method of regu: lating the cooling effect ofcooling means for cooling rooms or goods.

According to my invention the container or the tube containing thecooling means such as a volatile liquid, brine or solid carbon d1-oxide, is not in direct contact with the room or goods to be cooled. Iuse a double walled container or a double walled tube for the coolingmeans, and thus the exchange of heat between the cooling room and thecooling means is due to the molecules of the gas in the space betweenthose two walls. If there is a high vacuum in this space between the twowalls no transmission of warmth can take place.

It is the aim of my invention to regulate the transmission of warmth bychanging the pressure of the gas enclosed in the space between the twowalls. 4

My invention is further adapted to regulate the pressure of the gas inaccordance with the temperature of the cooling room or of the goods tobe cooled, and to do this fully automatically, thus providing athermostat which keeps up a constant temperature.

The change of the pressure of the enclosed gas can be effected with theaid of a pump connected with the room in which the gas is enclosed,creating a vacuum in this room when the temperature in the cooling roomis low enough.

A by far better way to re ulate the pressure of the enclosed as is toadsorb the gas with the aid of adsor ing material, such as silicagel,active coal, or the like. According to one form of my invention thecontainer with the adsorbing material is installed inside the coolingroom in order to be influenced by its temperature.

The container for the adsorbing material is' connected with the spacebetween the two walls of said double walled container or tube for thecooling means by a tube. This tube is preferably made with a capillarydiameter to avoid a disturbing difi'usion of the two walls. VVhen thetemperature in the cooling room rises, gas is desorbed from theadsorbing material and enters the space between the two walls, raisingthe pressure of the enclosed gas and transporting warmth from the outerwall which is in Contact with the air of the cooling room to the innerwall which is in contact with the cooling means.

So the cooling room gets cooled and likewise the container with theadsorbing material. Then the gas is adsorbed again and the pressure inthe space between the two walls is reduced.

In the annexed drawing the object of the invention is illustrated by wayof example. In this exemplification a cooling room (l2) shown partlywith its walls (11)is cooled with the aid of solid carbon dioxide. The

container (l) for the 'carbon dioxide (5) is dou le walled and the space(4) between the two walls (2) and (.3) is filled with gas, the pressureof which can be varied. The container (1)'is connected with a container(9) by a capillary tube (7) The adsorbing material (10) in the container(9) is prevented by a filter (8) from penetrating into the connection'tube (7).

I prefer to use a gas of high molecular weight, e. g. carbon dioxide,with a suitable adsorption character. Of course it depends too on theapplied temperatures, which of the various gases is to be used asfilling gas. For instance, under certain conditions hydrogen would be asatisfactory gas to use.

A special advantage of a thermostat based on this new method is tofunction reliably even at very low temperatures.

An apparatus as shown in the drawing can be made preferably of glassorder to secure a ood vacuum. When used in connection with tubescontaining brine, or with evaporators of refrigerating machines, sheetmetal is used as material for such a thermostat.

It will be clear from the preceding explanation that my invention isbased upon two principles, namelyfirst, that any material (like silicagel, charcoal, etc.) has definite adsorption ratesatvarious'temperatures; and second, that the conduction of 7 a vacuum.space depends primarily upon the pressure of gas within the space. Thesetwo principles are utilized for automatically regulating the temperatureof a room or the like. .-My invention has nothing to do with a secondaryrefrigerating cycle, ;as in prior devices, but 0 erates wholly on aconductivity principle.

en the gaseous pressure in bulb 9 is less. than the pressure in space4:, the material 10 v withdraws gas from the space and thereby reducesits conductivity. This occurs when the temperature in room 12 reaches apredetermined low limit. On the other hand, when the tem erature in room12 rises to a certain ;point, t e material 10 gives up some of theadsorbed gas which now flows into space 4 and-increases itsconductivity. It will thus be seen that the capillary tube .7 is not forthe urpose of permitting a circulation of as, ut to permit the flowofgas either from ulb 9 to space 4 or in the reverse direction.

I have herein described and shown the method and one practicalconstruction, especially for the use of solid carbonic dioxide, but itwill be apparent that thc construction is susceptible of embodiment invarious alternative forms and I therefore reserve the privilege ofresorting to all such legitimate changes as may be fairly embodiedwithin the irit and the scope of the invention as aimed in the appendedclaims. .7

What I claim is: p

1.. The method of automatically regulatingthe cooling efl'ect of coolingmeans, which comprises separating the cooling means from the room torbecooled by a closed space containing a suitable gas, and subjecting saidgas to the action at an adsorbing medium whose term rature 'depends uponthe temperature 0 said room, whereby said medium withdraws gas from saidspace '"when the room'temperature falls to decrease the heatcpnductivity of said space, and whereby said medium atrising roomtemperature gives up adsorbed gas which flows into said space toincrease its conductivity.

2. Refrigerating apparatus comprising a chamber to be cooled, adouble-walled container in said chamber adapted to hold a refrigerant,the space between said walls being closed and adapted to containasuitable gas, and a closed receptacle communicating with said splace andcontaining adsorbing material, w ich. is subJected to the temperature ofthe chamber, said material automatically withdrawing gas from said spaceto decrease its heat conductivity when the temperature of the chamberfalls, whereas an increase in the temperature of the chamber causes saidmaterial to give up adsorbed gas which flows into said space to increaseits conductivity.

In testimon whereof I aflix-my si ature.

lETER SCHLUMB HM.

